紫外分光光度法测定猪血中提取免疫球蛋白IgG含量的可行性研究

[目的]探讨紫外分光光度法测定猪血中IgG含量的可行性.[方法]采用饱和硫酸铵法从新鲜猪血中提取IgG,并采用紫外分光光度法测定提取猪血中IgG含量.[结果]将从猪血中分离的免疫球蛋白IgG于40℃下静置40 min,pH为7.4时,获得最多IgG的硫酸铵浓度为30％ ～ 35％.[结论]紫外分光光度法可用于测定猪血中IgG含量,该方法数据稳定,线性关系好,准确性高,操作简便,适合推广.     

脲铵氮肥施肥方式及用量对玉米产量及产量构成因素的影响

[目的]为摸清脲铵氮肥在玉米生产上的应用效果。[方法]以夏玉米为试验材料,通过田间小区试验,研究脲铵氮肥对玉米产量及产量构成因素的影响。[结果]脲铵氮肥肥效长,具有和尿素一样的增产效果,能明显改善玉米农艺性状和经济性状,增加产量。同时,脲铵氮肥养分减量40%施用(即只需使用纯氮60%的等量脲铵氮肥),就与尿素常规传统施肥方式取得相同的增产效果,投产比高,经济效益显著。[结论]该研究可为脲铵氮肥大面积推广应用提供科学的理论指导。     

Comparison of predictions of baking volume using large deformation rheological properties

Three large deformation rheological tests, the Kieffer dough extensibility system, the D/R dough inflation system and the 2 g mixograph test, were carried out on doughs made from a large number of winter wheat lines and cultivars grown in Poland. These lines and cultivars represented a broad spread in baking performance in order to assess their suitability as predictors of baking volume. The parameters most closely associated with baking volume were strain hardening index, bubble failure strain, and mixograph bandwidth at 10 min. Simple correlations with baking volume indicate that bubble failure strain and strain hardening index give the highest correlations, whilst the use of best subsets regression, which selects the best combination of parameters, gave increased correlations with R²=0.865 for dough inflation parameters, R²=0.842 for Kieffer parameters and R²=0.760 for mixograph parameters.     

猪组织中硫酸头孢喹肟含量测定和肌注给药残留研究

建立了硫酸头孢喹肟在仔猪组织内残留的高效液相色谱分析法.色谱条件:采用C18色谱柱(4.6 mm×150 mm,5μm),称取一水合高氯酸钠3.45 g溶于1 000 mL水中,加磷酸12 mL,用三乙胺调至pH3.6,将此溶液与乙腈按90∶10的比例混合作为流动相,紫外检测波长为270 nm.将头孢喹肟以20、100、500μg/kg分别添加到空白组织中,测得肌肉、肝脏、肾脏、肺脏、脂肪+皮肤组织中头孢喹肟回收率均在78%以上,平均回收率分别为81.57%、82.42%8、1.29%8、3.97%、78.80%.日内变异RSD在1.82%~6.25%之间,日间变异RSD在1.11%~6.35%之间.该方法的最低检测限为20μg/kg,在20~500μg/kg范围内时,线性关系良好.以2 mg/kg的剂量肌肉注射2.5%头孢喹肟注射液,连续用药5 d,于最后1次给药后测定不同组织中头孢喹肟的浓度.结果表明,停药后各组织中头孢喹肟浓度逐渐下降;最后一次注射后的第4 d,肺脏、脂肪+皮肤中已经检测不到头孢喹肟;最后一次注射后的第5天,所有组织均检测不到头孢喹肟.建议休药期为3 d.     

冷冻干燥法制备速溶植酸酶的研究

采用毕赤酵母发酵制备酶液,膜超滤浓缩、硫酸铵盐析法沉淀酶蛋白,结合冷冻干燥法制得速溶型植酸酶。结果表明,对酶活力达19 500U/ml的发酵液进行浓缩后,以70%饱和度的硫酸铵进行盐析,分离后的酶蛋白经过冷冻干燥得到活力为500 000U/g的植酸酶,速溶性好,溶解后清亮透明。酶的冻干粉50℃保存90d内酶活力仍能维持96%以上的活力。为高酶活速溶植酸酶的工业化生产提供了一条可行的思路。     

Aluminium-tolerant regenrants from potato cell cultures

Summary Cell cultures were developed from dihaploid clones ofSolanum tuberosum L. Selection in cell suspensions as well as plating of cells on selective medium supplemented with 5 mmol Al produced tolerant cell lines. The constancy of Al-tolerance of cell lines was confirmed by culturing the calli for 3 months in Al-free medium and then transferring them back to selective medium. 4 tolerant regenerant clones were obtained which maintained Al-tolerance also after subculture in control medium. Two of the 4 clones that constantly maintained Al-tolerance, originated from cell lines subcultured for 5 months under stress conditions. However, the regeneration rate of these cell lines was low compared with that of lines obtained after a shorter selection period.     

Purification of IgG from serum with caprylic acid and ammonium sulphate precipitation is not superior to ammonium sulphate precipitation alone

Immunoglobulin G (IgG) from bovine serum raised against Aeromonas Salmonicida was purified by ammonium sulphate precipitation (ASP) or caprylic acid treatment followed by ammonium sulphate precipitation (CAAS). Purity of IgG samples prepared by both methods were examined by High Performance Gel Permeation Chromatography, electrophoresis and antibody activity assay. Results suggest that IgG prepared by ASP is better than that obtained by CAAS method in terms of the yield of the IgG monomers and the recovery of the antibody activity.     

Silver nitrate and adenine sulphate induced high regeneration frequency in the recalcitrant plant Cosmos bipinnatus using cotyledon explants

Plant regeneration ability was studied in the medicinal-ornamental plant, Cosmos bipinnatus ‘Sonata white’, which is a dicotyledonous recalcitrant plant to shoot induction. Cotyledons were used as sources of explants to investigate plant regeneration. High frequency of direct shoot induction was obtained when BA (5 mg/l) and AgNO₃ (5 mg/l) were used in combination with 20 mg/l adenine sulphate (73.8%) in Murashige and Skoog (MS) medium. The highest shoot number per explant (5.7) was induced on MS medium supplemented with 5 mg/l BA, 5 mg/l AgNO₃, and 40 mg/l adenine. Eight week-old shoots were transferred to root induction media containing MS and half-strength MS medium with different concentration of IBA. The highest rate of root induction (70.8%) was obtained on half-strength MS medium with 1.5 mg/l IBA within four weeks. The plantlets were transferred to pot and kept in the greenhouse condition. Seventy percent of the plantlets successfully acclimatised.

Abbreviations: BA, 6-benzylaminopurine; IBA, Indole-3-butyric acid; MS, Murashige and Skoog; PGRs, plant growth regulators.